ul·tra·short 
(ŭl′trə-shôrt)
(ŭl′trə-shôrt)adj.
1.
a. Of or relating to radio waves with a wavelength less than 10 meters (33 feet).
b. Of or relating to optical pulses with typical durations of femtoseconds.
2. Of extremely short duration: an ultrashort flash.
3. Extremely short: an ultrashort skirt.
4. Of or relating to fixed-income investments with extremely short maturities, usually less than one year.